Semiconductor device with junction isolation

• US 6,525,340 B2
• Filed: 06/04/2001
• Issued: 02/25/2003
• Est. Priority Date: 06/04/2001
• Status: Expired due to Fees

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Colavito, David, Rovedo, Nivo
• Primary Examiner(s): Nelms, David
• Assistant Examiner(s): Nguyen, Dao H.
• Application Number:
  US09/873,497
• Publication Number:
  US 20020179905A1
• Time in Patent Office: 631 Days
• Field of Search: 257/57, 257/77, 257/347, 257/350, 257/611, 257/617, 438/302, 438/305
• US Class Current: 257/57
• CPC Class Codes: H01L 21/26586 characterised by the angle between the ion beam and the crystal planes or the main crystal surface
• CPC Class Codes: H01L 21/7624 using semiconductor on insulator [SOI] technology H01L21/76297 takes precedence; manufacture of integrated circuits on insulating substrates H01L21/84; silicon on sapphire [SOS] technology H01L21/86
• CPC Class Codes: H01L 29/66484 with multiple gate, at least one gate being an insulated gate H01L29/66742 takes precedence
• CPC Class Codes: H01L 29/66651 with a single crystalline channel formed on the silicon substrate after insulating device isolation
• CPC Class Codes: H01L 29/66659 with asymmetry in the channel direction, e.g. lateral high-voltage MISFETs with drain offset region, extended drain MISFETs
• CPC Class Codes: H01L 29/66666 Vertical transistors H01L29/66712, H01L29/66742 take precedence
• CPC Class Codes: H01L 29/7827 Vertical transistors H01L29/7802, H01L29/78642 take precedence
• CPC Class Codes: H01L 29/7831 with multiple gate structure FinFETs or MuGFETs H01L29/7855, thin film transistors H01L29/78645
• CPC Class Codes: H01L 29/7834 with a non-planar structure, e.g. the gate or the source or the drain being non-planar

Abstract

A field effect transistor (FET) is disclosed. In an exemplary embodiment of the invention, the FET includes an active semiconductor region defined upon a substrate, the active semiconductor region further having a mesa region formed therein. The FET also includes a gate formed within the active semiconductor region, the gate abutting the mesa region along one side thereof. The FET further includes a source region defined within a first area of the semiconductor region, the first region being located over an insulating layer, and a drain region defined within a second area of the semiconductor region, the second area also being located over the insulating layer. The first and second areas of the semiconductor region are located on opposite sides of the mesa region, and the insulating layer isolates the source region and the drain region from the substrate. In another exemplary embodiment, one of the source region or drain region is defined within a top surface of the mesa region.

Claims

1. A field effect transistor (FET), comprising:

an active semiconductor region defined upon a substrate, said active semiconductor region further having a mesa region formed therein;

a gate formed within said active semiconductor region, said gate abutting said mesa region along a side thereof;

one of a source region or a drain region defined within a first area of said semiconductor region, said first area of said semiconductor region being located over an insulating layer and not including said mesa region; and

the other of a source or a drain region defined within a top surface of said mesa region;

wherein said insulating layer isolates said one of a source region or a drain region within said first area of said semiconductor region from said substrate.

2. The FET of claim 1, wherein said drain region is defined in said first area of semiconductor region and said source region is defined within said top surface of said mesa region.

3. The FET of claim 2, wherein said source region has a different dopant concentration than said drain region.

4. The FET of claim 2, wherein said source region has a higher dopant concentration than said drain region.

5. The FET of claim 2, further comprising:

a first dopant implantation, into said source region; and

a second dopant implantation, into both said source region and said drain region, said first and second dopant implantations resulting in said source region having a higher dopant concentration than said drain region.

6. The FET of claim 5, further comprising:

a drain extension implant region, said drain extension implant region formed prior to said second dopant implantation.

7. The FET of claim 2, wherein said active semiconductor region further comprises:

said insulating layer formed upon said substrate;

a window opening formed within said insulating layer; and

an epitaxial layer grown over said insulating layer and said window opening;

wherein mesa region is formed over said window opening.

8. The FET of claim 7, wherein said insulating layer further comprises a dielectric pad layer deposited upon said substrate.

9. The FET of claim 8, wherein said substrate further comprises single crystalline material beneath said window opening.

10. The FET of claim 9, wherein:

said substrate further comprises single crystalline silicon; and

said epitaxial layer comprises single crystalline silicon where said epitaxial layer is grown over said window opening.

11. The FET of claim 10, wherein said epitaxial layer comprises polycrystalline silicon where said epitaxial layer is grown over said dielectric pad layer.

12. The FET of claim 10, wherein said epitaxial layer comprises amorphous silicon where said epitaxial layer is grown over said dielectric pad layer.

13. The FET of claim 7, wherein said gate surrounds said mesa region.